<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>Test</title>
</head>
<body>  
  <p> Hello! I'm <span id="input"></span>.</p>
  
  <script>
      document.getElementById('input').innerHTML = "Robert" ;
  </script>
</body>
</html>